Plunging Ranula

plunging ranula MRI

There is a well-defined cystic lesion (T2-hyperintense) within the right sublingual space. It dives anteriorly through a mylohyoid defect into the right submandibular space anterior to the right submandibular gland. The appearances are classical for diving or plunging ranula. The coronal T2W MR shows this to advantage.

Collectively, the mucocele, the ranula, and the cervical, or plunging ranula are clinical terms for a pseudocyst that is associated with mucus extravasation into the surrounding soft tissues. These lesions occur as the result of trauma to the salivary gland excretory duct, although obstruction of salivary flow is implicated in some instances.

Ranulas, which involve the major salivary glands, are divided into 2 types: oral ranulas and cervical ranulas. Oral ranulas are secondary to mucus extravasation that pools superior to the mylohyoid muscle, whereas cervical ranulas are associated with mucus extravasation along the fascial planes of the neck.

Reference: Coit W, Harnsberger H, Osborn A, Smoker W, Stevens M, Lufkin R. Ranulas and their mimics: CT evaluation. Radiology 1987; 163:211-216.

Credit: Dr Abhijit Datir